What do parents do during ABA?

Can you explain, in simple terms, what exactly do parents do during Applied Behavior Analysis (ABA) therapy sessions with their children? Do they actively participate, observe, or is their role more supportive in nature? Are there specific techniques or strategies that parents are encouraged to use at home to reinforce the learning and progress made during therapy? Understanding the parent's role in ABA can be crucial for ensuring a child's overall success and development.